Accompanying the reduced size and the increasingly advanced functions of cell phones and other electronic devices, there is a growing demand for the lithium ion secondary batteries used in these devices to have lighter weight, increased capacity and longer life (cycling adaptability). However, since oxides of cobalt and manganese having high specific gravity are used for the positive electrode active materials of lithium ion secondary batteries primarily used at present, the lithium ion secondary batteries are heavy. Therefore, although reducing the ratio of positive electrode active material in the entire lithium ion secondary battery can be considered for reducing the total weight of lithium ion secondary batteries, in this case, there is a high likelihood that capacity and lifetime (cycling adaptability) cannot be expected to improve even though a reduction in weight can be achieved.
Extensive studies have been conducted in recent years on whether or not organic compounds composed of light elements and the like can be applied for use as positive electrode active materials. Pi-conjugated, electrically conductive polymers are particularly promising for use as positive electrode active materials. For example, Patent Document 1 describes a secondary battery that uses a novel polyaniline derivative compound of an electrically conductive polymer enabling one-step, two-electron transfer, and the use of a protonated form of the compound in a positive electrode. According to Patent Document 1, since an electrode material using the novel polyaniline derivative compound has high energy density, the use of that electrode material as a positive electrode is described as being useful in a secondary battery that uses a zinc plate for the negative electrode and an aqueous zinc sulfate solution for the electrolyte solution. However, in terms of increasing capacity and lengthening lifetime (cycling adaptability), further improvements are being sought, and extensive studies are currently being conducted as to whether or not novel organic compounds and the like can be applied to positive electrode active materials for lithium ion secondary batteries.
Patent Document 2 describes a production process for generating pentacene by irradiating an oxygen adduct of a pentacene derivative with ultraviolet light. According to Patent Document 2, this production process is described as being highly superior in terms of being environmentally clean since it does not generate harmful gas and can be easily recycled, while at the same time enabling optical patterning, thereby reducing the burden on the environment and natural resources.